The present invention relates to a base unit for a cross flow, tube and shell type heat exchanger. It also relates to a heat exchanger module comprised of such base units, and to a heat exchanger comprised of such modules.
Heat exchangers are used in a great many industrial processes in which heat has to be transferred from a hot fluid which is consequently cooled, to a cold fluid which is consequently heated. While these devices are basically simple, having for instance no moving parts, there are nevertheless some serious problems which the designer of heat exchangers must solve. The material the heat exchanger is made of must not only withstand the temperature of the hot fluid, which is obvious, but must also be able to handle chemically aggressive media such as acids, bases, brines, alkalies, etc. Heat exchangers must also withstand mechanical stresses produced by the elevated pressures of the fluids handled as well as by thermal expansion. While there exist materials that meet these conditions, such as certain stainless steels, they are very expensive and not easily processed.
Attempts have therefore been made to make such heat exchangers from plastic materials. These attempts were, however, only partly successful, with such problems as distortion due to thermal stresses, tightness of seals, compactness, etc., still largely unsolved.
It is one of the objects of the present invention to overcome the disadvantages of the prior-art heat exchangers and to provide a plastic base unit for a tube and shell type heat exchanger which, integrally, contains the essentials of such a heat exchanger, namely a shell element and a tube element, from a plurality of which base units it is possible to produce a heat exchanger module which, in turn, can be combined with other such modules to produce a complete heat exchanger that is compact, stable, tightly sealed, not distorted by thermal stresses, withstands most chemical agents, and is easily disassembled for inspection, cleaning and possible replacement of components.